Exclusive: New TTRO to be made for M48 Severn Bridge weight restrictions

National Highways has confirmed that a new Temporary Traffic Regulation Order (TTRO) covering the new M48 Severn Bridge weight restrictions, preventing vehicles over 7.5 tonnes from using the structure, will come into effect from next month.

The new restrictions came in after inspections revealed an increase in corrosion of the main cables of the bridge, prompting the National Highways to impose the restrictions to decrease the live load of the bridge.

National Highways said that a 2022 TTRO that had covered restrictions on vehicles over 7.5 tonnes on lane two of the bridge expired in September 2023, meaning that the bridge has been operating with unenforceable weight restrictions, despite red circled signs being displayed since then.

Speaking to Highways, National Highways said ‘we are not aware of any prosecutions’ that took place since the 2022 TTRO expired and that a new TTRO was not issued ‘due to the cable inspections and subsequent lab work’.

Built in 1966, the Severn Bridge previously carried the M4, but following the opening of the Prince of Wales Bridge in 1996, the Severn was redesignated as the M48.

Both bridges carry England and Wales bound traffic, but the advanced age of the Severn Bridge has meant that it has experienced more corrosion and deterioration, with the M4 Prince of Wales Bridge serving as the alternative route for HGVs directed away from the older structure.

The expired TTRO from 2022 was put in place after it was discovered in February of the same year that National Highways had failed to renew the previous traffic order, which had expired three years prior.